A large number of patients suffer from respiratory diseases, such as chronic obstructive pulmonary disease (COPD). Due to diminished effectiveness of lungs of such patients, those patients require supplemental oxygen support for comfort and activity. Typically, the oxygen used by these patients is provided as pressurized gas, or as liquefied oxygen, which enables more compact and lightweight storage than gaseous oxygen, and is especially useful during patient mobility. Although most liquid oxygen is delivered from central sources, on-site liquefying of oxygen has been known to be performed by conventional cryocoolers. Such conventional cryocoolers include a refrigeration cycle that is powered by a motor. Such a motor includes a stator and a piston, both of which are incorporated along with numerous other elements (for example, various elements made of high permeability materials, such as iron, electrical steel, yoke, and other like materials) within a pressurized vessel to contain the high-purity working gas within, typically ultrapure helium that remains gaseous at low temperatures when all other substances become liquid or solid. The structure of this traditional motor is very complex, and the electromagnetic stator, which may suffer failures in wires or their insulation, can be repaired or replaced only by breaking or opening the pressurized vessel. Accordingly, the conventional motors and associated cryocoolers are very expensive.